On left side of the control board will be the test terminals, short them with screwdriver and the diagnostic light will flash an error code

No power

• Starter or breaker tripped possible faulty compressor start windings, a hard start kit can be used to make unit work but with my experience it only lasts a few months.

2 Flash high-pressure problems red wires run to HP switch

• Water Condenser should have 10-degree difference between water going in and water going out.
• Refrigerant charge could be over charged check subcooling.
• Faulty high-pressure switch test switch at normal pressures it should be normally closed.
• In heating mode possible low/no airflow over the Evaporator.
• Faulty TXV bulb loss of charge or plug/stuck valve

My experience 1
Refrigerant 410a
cooling H-600 PSI L-50 PSI and dropping frost between TXV and air coil, trip on high pressure Heating H-350 PSI L-75 PSI cold between TXV and water condenser, trip on water coil low temperature Found TXV stuck closed I replaced both filter/dryers, TXV, vacuum to 500 microns, new refrigerant system works perfectly now H-350 L-150

My experience 2
Refrigerant 410a
H-350 L-125 high-pressure switch open. Faulty switch need to recover refrigerant replace high-pressure switch (one two red wires run to) and two filter/dryers. Leak test with 150-PSI nitrogen, Vacuum down to 500 microns. Recharge

3 Flashes low pressure/ loss of charge Blue & Brown wires to LP/LOC switch

Refrigerant charge lost due to leak

Most leaks will be found at the access fittings where we connect our gauges. I have found leaks at water condenser, Evaporator, and on copper line where they had rubbed against each other until it created a hole. If 0 pressure leak search with 150 Lb nitrogen repair leak vacuum all moisture out of system to 500 microns, recharge by weighing in refrigerant.

When arriving at a system you find it has 0 PSI Refrigerant pressure most likely the leak will be located on the liquid or discharge side of the system. Climate Master leaks are very hard to find in the past I have found them on the evaporator. Pressure tests may seem to hold due to the small leak, But if 0 PSI then you do have a leak. Look for oil stains anywhere on piping pressure test, refrigerant leak detector until you find the leak.

4 flashes Water coil low temperature limit grey wires to FP1 sensor

• Cooling mode reduced or no water flows to water condenser.
• Bad thermistor click here to see Temp/Ohm chart and compare. Temp/Ohm chart on page 11
• Faulty TXV bulb loss of charge or plug/stuck valve

My experience Refrigerant 410a
cooling H-600 PSI L-50 PSI and dropping frost between TXV and air coil, trip on high pressure Heating H-350 PSI L-75 PSI cold between TXV and water condenser, trip on water coil low temperature
Found TXV stuck closed I replaced both filter/dryers, TXV, vacuum to 500 microns, new refrigerant system works perfectly now H-350 L-150

5 Flashes Air coil low temperature limit Violet wires to FP2 sensor

• low refrigerant charge
• faulty TXV
• cooling mode reduced or no air flow.
• Bad thermistor click here to check Temp/Ohm chart and compare. Temp/Ohm chart in page 11

My experience

Blower motor seized or low air flow

low refrigerant Refrigerant 410a high-240 low-55 superheat 77 subcooling 0
Found high service valve leaking – replace cores and caps. Recharge unit with 2lb 6 oz high- 320 low-120 superheat 9 subcooling 10

6 Flashes Condensate fault Yellow wire to condensate sensor

• Blocked drain.
• Always have Trap installed next to heat pump.

7 Flashes over/under voltage

• Compare main power supply voltage and 24VAC before and during operation.

Thank you for visiting my blog I would appreciate any feedback I can get, Please leave a comment on whether my information has helped you. I am always interested in more topics to write so feel free to leave a comment asking about anything related to HVAC-R (Heating, Ventilation, air conditioning, refrigeration).

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Tagged: climate master, Heat pump, high pressure, TXV